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Make C++11 fusion::vector more consistent with C++03 fusion::vector

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- Construct from elements is enabled iff each argument is_convertible to
    corresponding element.
  - Construct from sequence is enabled iff the single argument is a fusion
    sequence.
  - C++11 vector and tuple also disable construct from sequence that are
    shorter than the destination. C++03 gives incorrect is_convertible
    responses in this situation and fails to compile if that constructor is
    used; C++11 can have instantation errors in
    and_<is_convertible<U, T>...> without the additional check.
  - C++11 tuple and vector support truncation conversion and assignment like
    all other sequences.
This commit is contained in:
Lee Clagett
2016-08-26 12:45:11 -04:00
parent 55150a7fa6
commit 5906d9c316
22 changed files with 1504 additions and 283 deletions
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test/sequence/tuple_traits.cpp
+46 -83
View File
@@ -11,15 +11,11 @@
#include <boost/type_traits/is_constructible.hpp>
#include <boost/type_traits/is_convertible.hpp>
struct test_conversion
{
test_conversion(int) {}
};
#define FUSION_SEQUENCE boost::fusion::tuple
#define FUSION_ALT_SEQUENCE boost::fusion::vector
#include "traits.hpp"
struct test_no_conversion
{
explicit test_no_conversion(int) {}
};
struct not_convertible {};
/* Some construction differences in fusion::tuple from std::tuple:
- Construction from elements cannot call an explicit constructor.
@@ -35,89 +31,56 @@ struct test_no_conversion
These differences are historical. Matching the behavior of std::tuple
could break existing code, however, switching to fusion::vector would
restore the historical behavior. */
int
main() {
{
using namespace boost;
using namespace boost::fusion;
int
main()
{
using namespace boost::fusion;
BOOST_TEST(!(is_convertible<int, tuple<> >::value));
BOOST_TEST(!(is_convertible<int&, tuple<> >::value));
test_convertible(false /* no conversion construction */ );
BOOST_TEST(!(is_convertible< int, tuple<int> >::value));
BOOST_TEST(!(is_convertible< int&, tuple<int> >::value));
BOOST_TEST(!(is_convertible< vector<int>, tuple<int> >::value));
BOOST_TEST(!(is_convertible< vector<int>&, tuple<int> >::value));
BOOST_TEST((is_convertible<std::pair<int, int>, tuple<int, int> >(true)));
BOOST_TEST((
is_convertible<std::pair<int, int>, tuple<convertible, int> >(true)
));
BOOST_TEST((
is_convertible<std::pair<int, int>, tuple<int, convertible> >(true)
));
BOOST_TEST((
is_convertible<
std::pair<int, int>, tuple<convertible, convertible>
>(true)
));
BOOST_TEST(!(is_convertible<int, tuple<int, int> >::value));
BOOST_TEST(!(is_convertible<int&, tuple<int, int> >::value));
}
#if defined(FUSION_TEST_HAS_CONSTRUCTIBLE)
test_constructible();
// is_constructible has some restrictions ...
#if !(defined(BOOST_NO_CXX11_DECLTYPE) || defined(BOOST_NO_CXX11_TEMPLATES) || \
defined(BOOST_NO_SFINAE_EXPR))
{
using namespace boost;
using namespace boost::fusion;
BOOST_TEST((is_constructible< tuple<> >(true)));
BOOST_TEST((is_constructible<tuple<>, int>(false)));
BOOST_TEST((is_constructible< tuple<> >::value));
BOOST_TEST(!(is_constructible<tuple<>, int>::value));
BOOST_TEST(!(is_constructible<tuple<>, int&>::value));
BOOST_TEST((is_constructible< tuple<int> >(true)));
BOOST_TEST((is_constructible<tuple<int>, int>(true)));
BOOST_TEST((is_constructible<tuple<convertible>, int>(true)));
BOOST_TEST((is_constructible<tuple<not_convertible>, int>(false)));
BOOST_TEST((is_constructible< tuple<int>, vector<int> >(false)));
BOOST_TEST((is_constructible<tuple<int>, int, int>(false)));
BOOST_TEST((is_constructible< tuple<int> >::value));
BOOST_TEST((is_constructible<tuple<int>, int>::value));
BOOST_TEST((is_constructible<tuple<int>, int&>::value));
BOOST_TEST((is_constructible<tuple<test_conversion>, int>::value));
BOOST_TEST((is_constructible<tuple<test_conversion>, int&>::value));
BOOST_TEST(!(is_constructible<tuple<test_no_conversion>, int>::value));
BOOST_TEST(!(is_constructible<tuple<test_no_conversion>, int&>::value));
BOOST_TEST(!(is_constructible< tuple<int>, vector<int> >::value));
BOOST_TEST(!(is_constructible<tuple<int>, vector<int>&>::value));
BOOST_TEST(!(is_constructible<tuple<int>, int, int>::value));
BOOST_TEST(!(is_constructible<tuple<int>, int&, int&>::value));
BOOST_TEST((is_constructible< tuple<int, int> >::value));
BOOST_TEST((is_constructible<tuple<int, int>, int, int>::value));
BOOST_TEST((is_constructible<tuple<int, int>, int&, int&>::value));
BOOST_TEST((
is_constructible<
tuple<test_conversion, test_conversion>
, int
, int
>::value
));
BOOST_TEST((
is_constructible<
tuple<test_conversion, test_conversion>
, int&
, int&
>::value
));
BOOST_TEST(!(
is_constructible<
tuple<test_no_conversion, test_no_conversion>
, int
, int
>::value
));
BOOST_TEST(!(
is_constructible<
tuple<test_no_conversion, test_no_conversion>
, int&
, int&
>::value
));
BOOST_TEST((is_constructible< tuple<int, int> >(true)));
BOOST_TEST((is_constructible<tuple<int, int>, int, int>(true)));
BOOST_TEST((
is_constructible<tuple<convertible, convertible>, int, int>(true)
));
BOOST_TEST((is_constructible<tuple<int, not_convertible>, int, int>(false)));
BOOST_TEST((is_constructible<tuple<not_convertible, int>, int, int>(false)));
BOOST_TEST((
is_constructible<tuple<not_convertible, not_convertible>, int, int>(false)
));
#if defined(BOOST_FUSION_HAS_VARIADIC_VECTOR)
// C++03 fusion::tuple has constructors that can never be used
BOOST_TEST(!(is_constructible<tuple<int, int>, int>::value));
BOOST_TEST(!(is_constructible<tuple<int, int>, int&>::value));
#endif
BOOST_TEST(!(is_constructible<tuple<int, int>, int, int, int>::value));
BOOST_TEST(!(
is_constructible<tuple<int, int>, int&, int&, int&>::value
));
}
// C++03 fusion::tuple has constructors that can never be used
BOOST_TEST((is_constructible<tuple<int, int>, int>(false)));
#endif
BOOST_TEST((is_constructible<tuple<int, int>, int, int, int>(false)));
#endif // FUSION_TEST_HAS_CONSTRUCTIBLE
return boost::report_errors();
}